Abstract
The heat transfer and pressure drop characteristics of R290 flow boiling in a corrugated tube were investigated through computational fluid dynamics (CFD) in this study. We established a model of flow boiling in a corrugated tube with different corrugated structures (rectangular and circular corrugations) and validated the model using the Liu–Winterton and Xu–Fang empirical equations. The heat transfer coefficient (HTC) and pressure drop were obtained at a mass flow rate of 0.04–0.2 kg/s and a water inlet temperature of 310–330 K. The results show that the HTC and the drop in the pressure of the corrugated tubes both obviously increased compared with a smooth tube as the mass flow rate increased. The HTC decreased for the three tubes as the water inlet temperature increased, while the drop in pressure slightly increased for the three tubes. Moreover, the corrugated structure was found to significantly enhance the heat transfer; the heat transfer enhancement factor (E1) of the corrugated tube with the rectangular corrugations and the corrugated tube with the circular corrugations was 2.01–2.36 and 1.67–1.98, respectively. The efficiency index (I) for both the rectangular corrugated pipe and the circular corrugated pipe was greater than 1 (1.05–1.24 and 1.13–1.29, respectively). The application of corrugated tubes with round and rectangular corrugations can reduce the heat transfer area required for the exchange of heat and, thus, reduce the cost.
Highlights
The destruction of the ozone layer and greenhouse gas pollution are becoming increasingly serious and are environmental issues of global concern
As the saturation temperature increases from 273 K to 283 K, the heat transfer coefficient (HTC) is increased by about 4.8%, while the pressure drop is decreased by about 8.96%
The flow boiling of R290 in a smooth pipe and two corrugated pipes with a 5 mm inner diameter (ID) was investigated by numerical simulation in this study
Summary
The destruction of the ozone layer and greenhouse gas pollution are becoming increasingly serious and are environmental issues of global concern. According to the Montreal and Kyoto Protocols and a series of agreements, the HCFC and HFC refrigerants currently in general use should be gradually phased out due to their disadvantages, such as destruction of the atmosphere and aggravation of the greenhouse effect [1]. R290 (propane) has an Ozone Depletion Potential (ODP) of 0, a Global Warming Potential (GWP) of 20, a density of 580 kg·m−3, and the advantages of being non-toxic, chlorine-free, and low in carbon. The use of enhancement tubes with a small diameter provides an opportunity to reduce the size of heat exchangers by enhancing the heat transfer, which, in turn, can reduce the refrigerant charge of R290 to within the safe use range [7,8]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
